Prolactinoma

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Case history #1

A 27-year-old woman presents with amenorrhea. She had been taking the combined oral contraceptive pill for the last 9 years, stopping this 11 months ago. She is otherwise healthy, but on physical exam she has bilateral galactorrhea. Laboratory work-up reveals an elevated prolactin level of 150 micrograms/L (3000 mIU/L). Normal prolactin levels are up to 25 micrograms/L (500 mIU/L). She also had low-normal gonadotropin (luteinizing hormone [LH], follicle-stimulating hormone [FSH]) levels. Magnetic resonance imaging (MRI) examination of the pituitary sellar region depicts a 6 mm right-sided pituitary mass, with no suprasellar or parasellar extension.

Case history #2

A 45-year-old man presents with loss of libido and some erectile dysfunction. He is otherwise healthy. On physical examination he has mild bilateral gynecomastia and normal testes. Laboratory work-up reveals a highly elevated prolactin level of 2300 micrograms/L (46,000 mIU/L). Normal prolactin levels are up to 15 micrograms/L (300 mIU/L). He also has low testosterone, LH, and FSH levels. MRI exam of the pituitary sella depicts a large 32 mm pituitary macroadenoma with suprasellar extension and optic chiasmal compression. Visual field assessment reveals bitemporal hemianopia.

Other presentations

Prolactinomas, particularly where they are large tumors, can present with sudden headache, syncope, vomiting, fever, and visual impairment. All these symptoms may occur in the setting of pituitary apoplexy (a clinical syndrome resulting from acute hemorrhagic or ischemic infarction of a pituitary adenoma). Occasionally, prolactinomas are incidentally detected during imaging evaluation (computed tomography or magnetic resonance imaging) of the brain for other unrelated medical conditions. Infrequently, prolactinoma may be a component of the familial syndrome of multiple endocrine neoplasia syndrome type 1, together with primary hyperparathyroidism and neuroendocrine tumors, most commonly in the gastrointestinal tract.

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